基于MOOSE平台的高阶全隐式核反应堆一回路系统分析

Based on the multi-physics coupling platform MOOSE (Multiphysics Object Oriented Simulation Environment), the modular system safety analysis code, ZEBRA, was developed. The high-order and fully-implicit discrete format was presented to establish the nuclear reactor primary loop model. And the coupling calculation of nuclear reactor system including neutron diffusion, two-dimensional solid heat conduction, and one-dimensional fluid were also implemented. For the problem of flow and heat transfer in a single pipe, the ZEBRA code is coupled and verified, and the solution accuracy of first-order and second-order spatial discrete formats under steady-state conditions and Implicit-Euler, Crank-Nicolson and BDF2 schemes under transient conditions are compared, and the steady-state and power-reducing transient conditions of PWR loop system are simulated and analyzed. The results show that the high-order spatial discrete format has a higher accuracy, and the BDF2 time discrete format is in best agreement with the theoretical solution. The temperature, velocity, and pressure distribution of the PWR loop system are reasonable. The steady-state and transient calculation results are in good agreement with those of RELAP5.